Most current computers utilize keyboards that are physically connected to the computer by a cable. By pressing a key on the keyboard, the keyboard generates a "make" code which is transmitted over the cable to the computer. Releasing the key generates a corresponding "break" code which is sent over the cable. Each key on the keyboard has a corresponding "make" and "break" code, thereby identifying which key is depressed and released. When a key is depressed and the "make" code is transmitted to the computer, upon receipt of the "make" code, the computer responds to the code accordingly, such as by displaying a character on its display. Generally, if the key is not released, the keyboard will continue to generate the corresponding "make" code until the key is released. In normal operation, the computer will respond to the receipt of each "make" code, such as by repeating the associated character displaying on the computer display.
The wired keyboard as described above, has proven to be very reliable and perform very well. However, as the computer industry is a very competitive and rapidly changing industry, computer manufacturers must continuously introduce new products to the market to ensure their competitiveness and profitability.
In the design and manufacture of new computer systems, particularly of the personal computer ("PC") type, there is great pressure by consumers to introduce unique new functions and features for the computer.
An example of a design effort to expand the functions of a personal computer is the PC/TV convergence device. The PC/TV convergence device is a computer system having video/television capability converged therein, so that one computer system may be used as a computer and as a television/video set.
Stated another way, the PC/TV convergence device is a fully functional computer which also emulates a television, providing TV viewing (via broadcast, cable, Digital Satellite, or other broadcast media) and personal computing functionality. This convergence of computer and television provides a user with combined access to both television program information and computer functionalities.
Typically, a PC/TV convergence device consists of a fully functional computer including fax/modems, CD-ROM/DVD players, and media storage devices such as hard drives and floppy drives. The computer is interfaced with a video monitor, often a big screen television, with the television's NTSC interlaced signal being converted to a scan VGA signal or the computer's scan VGA signal being converted to an NTSC interlaced signal. Because the PC/TV convergence device is controlled by the computer's operating system, the PC/TV convergence device can, among other things, display PC applications and TV programs on a single monitor. The convergence of the personal computer and the television into a single device also permits the utilization of the communications bandwidth, mass storage and graphics of the computer to deliver, store and display applications during a traditional television viewing environment. The PC/TV convergence device also changes a typical television experience from just a passive viewing device to a user interactive device.
Some of the existing PC/TV convergence devices utilize wireless infrared keyboards to provide the user of the PC/TV convergence device greater freedom of movement as compared to keyboards physically wired to the computer. Infrared keyboards operate in a manner similar to that of wired keyboards through the transmission of an infrared signal, but can only operate in the "line of sight" from the keyboard to the computer. When a key is pressed on an infrared keyboard, and infrared "make" signal is sent from the keyboard's transmitter and received by an infrared receiver associated with the computer. When the key is released, an infrared "break" signal is transmitted from the infrared keyboard to the computer.
One significant problem with the infrared keyboard occurs when codes sent from the keyboard are not received by the computer. This may occur, for example, when someone walks between the keyboard and the computer when a user is utilizing the keyboard. This often creates undesirable results performed by the computer. For example, after a key is depressed, and the "make" code is sent from the keyboard to the computer, when the key is released, if the computer does not receive the "break" code, the computer may respond as if the key is still depressed.
Accordingly, it is desirable to provide a computer system utilizing an infrared wireless keyboard that can recover from "break" codes transmitted by the keyboard and not received by the receiver.